﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace WebsiteAdmin.Extensions
{
    public class ImgModify
    {
        public string GetMode(string orgPath)
        {
            System.Drawing.Image originalImage = System.Drawing.Image.FromFile(orgPath);
            string result = string.Empty;
            if (originalImage.Width > originalImage.Height)
                result = "W";
            else if (originalImage.Width < originalImage.Height)
                result = "H";
            else if (originalImage.Width == originalImage.Height)
                result = "HW";
            else
                result = "Cut";
            originalImage.Dispose();
            return result;
        }

        public void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
        {
            System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);
            int x = 0;
            int y = 0;
            int towidth = width;
            int toheight = height;
            int ow = originalImage.Width;
            int oh = originalImage.Height;
            switch (mode)
            {
                case "HW"://指定高宽缩放（可能变形） 
                    break;
                case "W"://指定宽，高按比例
                    toheight = originalImage.Height * width / originalImage.Width;
                    break;
                case "H"://指定高，宽按比例
                    towidth = originalImage.Width * height / originalImage.Height;
                    break;
                case "Cut"://指定高宽裁减（不变形）
                    if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                    {
                        oh = originalImage.Height;
                        ow = originalImage.Height * towidth / toheight;
                        y = 0;
                        x = (originalImage.Width - oh) / 2;
                    }
                    else
                    {
                        ow = originalImage.Width;
                        oh = originalImage.Width * toheight / toheight;
                        x = 0;
                        y = (originalImage.Height - ow) / 2;
                    }
                    break;
                default:
                    break;
            }
            //新建一个BMP图片
            System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);
            //新建一个画板
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);
            //设置高质量插值法
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
            //设置高质量，低速度呈现平滑程序
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
            //清空画布并以透明背景填充
            g.Clear(System.Drawing.Color.Transparent);
            //在指定位置并且按指定大小绘制原图片的指定部分
            g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight), new System.Drawing.Rectangle(x, x, ow, oh), System.Drawing.GraphicsUnit.Pixel);
            try
            {
              
                bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
            }
            catch (Exception e)
            {
                throw e;
            }
            finally
            {
                originalImage.Dispose();
                bitmap.Dispose();
                g.Dispose();
            }
        }
    }
}
